This wide-spread kind of device generally comprises a thermally insulating box forming the body of the device. This box contains at least one heating element, for example one or more resistors connected to a source of electric voltage. The box also contains a mobile housing in which a piece of bread to be toasted is placed, said housing being located near the resistors. The resistors are heated during a given time, after which the piece of toast is ejected from the device.
It is in particular known to include the resistors in tubes of quartz, in order to prevent the user from coming into contact with a naked conductor.
A toasting level of the bread is chosen by the user, classically by means of a cursor or of a serrated roller, before introducing the bread into the device. However, said cursor or said serrated roller is generally connected to means for determining the toasting duration. This duration, often approximate, does not correspond to a precise toasting quality for the bread. Indeed, for the same toasting duration, the result obtained in terms of visual aspect and taste varies according to the nature of the bread introduced. Variation factors are in particular the thickness of the bread slice and its percentage of moisture.
It is thus useful to be able to control visually the toasting progression for the bread, in order to stop it when it reaches the level desired by the user. A solution to this problem is provided by the invention described in the patent FR 2 799 632, in the name of the Applicant. This invention relates to a toaster whose side walls of the box are transparent. Thus, the bread slices introduced into the device can be seen during their toasting which can thus be stopped at the desired time.
According to a variant of the invention described in the patent FR 2 799 632, the heating elements are arranged in the upper and lower parts of the box, in order to clear the median part of said box. In this manner, the heating elements are not very visible by the user. He can thus control the toasting level for a piece of bread without its field of vision being obstructed by the presence of a heating element.
A disadvantage of positioning the heating elements outside the median part of the box is related to the toasting quality for the bread. Indeed, a bread slice introduced into such a device is more toasted near the heating elements, that is to say at the top and at the bottom, than in its median part. One thus obtains a not very homogeneous toasting, which is unsatisfactory for the consumer.
A known solution, described in the patent FR 2 799 632 consists in including the heating elements into reflector housings. These reflector housings have a generally bent shape, able to reflect a part of the infrared radiation of the resistors towards the bread slices, in particular towards their median part. These reflectors thus enable to homogenize the toasting of the bread if the heating elements are placed at the top and at the bottom of the box.
However, it happens that the result obtained is not sufficiently homogeneous for the taste of the consumer. There is thus a need to control the toasting level according to the zone of the bread slice.
Another disadvantage related to the position of the heating elements relates to the bread crumbs falling to the bottom of the device. Indeed, when introducing or ejecting the bread, crumbs can fall onto the heating elements and, if necessary, onto the reflectors. The heating elements concerned are mainly those being in a lower part of the box.
Because of their shape, in particular curved, the reflectors which receive bread crumbs keep these crumbs in the vicinity of, even in contact with, the heating elements. During toasting, these crumbs are brought up to a very high temperature. They calcine and give off smoke, which causes an embarrassment for the consumer and a risk of starting a fire.
Moreover, this calcination leaves unaesthetic traces on the heating elements and the reflectors. If the box is transparent, the interior of the device can be seen by the user. It is thus preferable to avoid the appearance of such traces of calcinations on the reflectors.